The influence of organic compounds on the development of precipitation acidity in maritime clouds

Abstract

Abstract. In order to estimate the anthropogenic influence of gas and aerosol emissions from the Petroleum Industry in maritime zones with clouds of small vertical extent, a numerical 1-D Eulerian cloud-chemical model with detailed microphysics (Alfonso and Raga, 2002) is used to simulate the influence of water soluble organic compounds (WSOC) and organic+inorganic gas emissions on cloud development. Following Mircea et al. (2002), we tested the sensitivity of the cloud and precipitation development in the classical inorganic case (CIC) and the inorganic+organic case (IOC) with respect to CCN compositions. The results indicate an increase in the droplet concentration for the IOC, and a delay in the development of precipitation.The pH spectral evolution was studied during both the development and precipitation stages. The influence of the diffusion of formic acid and its generation by oxidation of hydrated formaldehyde in the aqueous phase result in a reduction in the pH of precipitation in the range between 0.05 and 0.15 pH units (from 1 to 3%) for the high ambient SO 2 concentration (20 ppb) and between 0.2-0.5 pH units (from 4 to 10%) for the low ambient SO 2 concentration (1 ppb) case.

Influence of water‐soluble organic carbon on cloud drop number concentration

“…[54] While the results discussed up to now allow a direct comparison of the CCN activity by inorganics and organics, Mircea et al [2002] and Alfonso and Raga [2004] predicted an increase in CCN activity if insoluble material is replaced by WSOC. Mircea et al [2002] estimated the effects on the basis of equilibrium conditions; however, this approach represents an overestimate of DN d as qualitatively shown by Ming and Russell [2004].…”

A Monte Carlo Framework to Simulate Multicomponent Droplet Growth by Stochastic Coalescence

“…In the marine environment, the aerosol recycling process is believed to be the major mechanism responsible for the bimodal shape of the aerosol size distributions (Flossmann, 1994;Feingold and Kreidenweiss, 1996). The heterogeneous chemical reactions, which add nonvolatile solute to each cloud droplet, strongly depend on the salt content and pH of the droplet (Alfonso and Raga, 2004). Since aerosols also have a significant influence on cloud microphysics and cloud radiative properties, it is necessary to simulate aerosol processes realistically and with adequate accuracy.…”

Monte Carlo simulations of two-component drop growth by stochastic coalescence

“…In the marine environment, the aerosol recycling process is believed to be the major mechanism responsible for the bimodal shape of the aerosol size distributions (Flossmann, 1994;Feingold et al, 1996). The heterogeneous chemical reactions, which add nonvolatile solute to each cloud droplet, strongly depend on the salt content and pH of the droplet (Alfonso and Raga, 2004). Since aerosols also have a significant influence on cloud microphysics and cloud radiative properties, it is necessary to simulate aerosol processes realistically and with adequate accuracy.…”